New 'partial ping' from Flight 370 could show where plane went down

(CNN) – As investigators work backwards to help narrow the search zone for Malaysia Airlines Flight 370, some of the most critical information may come from the pings the plane sent out after it dropped off the radar.

These pings are almost like breadcrumbs, leaving behind a trail of clues about how long the plane was in the air after it made that southern turn.

But what could be most useful is a newly discovered so-called partial ping, which may indicate the moment Flight 370 crashed into the ocean.

CNN's aviation correspondent René Marsh reports.